Question: Why does my doctor want me to drink so much water?
Answer: Water, the most abundant substance in the body, is an essential component of all tissues. Our body loses water each day, mostly through perspiration and urination. This water must be replaced to prevent excessive fluid loss, which can lead to dehydration.
Persistent, unreplaced water loss can cause muscle weakness, fatigue, dizziness, headaches, confusion, forgetfulness, or an elevated heart rate. Chronic dehydration can also lead to painful kidney stones.
Dehydration is one of the most frequent causes of hospitalization after age 65.
Thirst indicates that you should drink. Because the sensation dissipates long before all water is replaced, however, it’s not a reliable indicator of the need for water especially in older people, who tend to have a reduced sense of thirst.
Urine concentration also indicates fluid status. Darkly colored urine is often too concentrated and suggests dehydration; clear urine is usually diluted, suggesting adequate fluid intake.
The National Academies of Science have established general fluid recommendations for adults: 91 ounces per day for women and 125 ounces per day for men. However, fluid needs are very unique to your size, weight, activity level, and the climate in which you live.
A general rule of thumb is to consume a half-ounce to an ounce of fluid for each pound of body weight. If you are active and live in a warmer climate, your fluid needs are likely on the higher end of the range. If you are sedentary and live in a cooler climate, your fluid needs are likely in the lower end of the range:
Did you know that 80 percent of your fluid intake comes from beverages, while the other 20 percent is derived from foods? To increase your fluid intake, drink more water as well as other fluids (such as broth) and eat foods that contain a large percentage of water (fruits, vegetables, and soups). Limit intake of alcoholic beverages since they have a dehydrating effect.
Don’t wait until you are thirsty to drink water — this is typically a sign that you are already dehydrated. To ensure that you are getting enough water throughout the day, carry a water bottle around with you wherever you go (in the car, when you go to the doctor’s office, etc.).
Sipping on water throughout the day is the easiest way to get enough fluid. Don’t wait to consume all of your water at once — you will likely feel too full to get in all of your required water for the day.
You may need more water when you exercise if the weather is unusually hot or cold, or if you have certain medical problems, including respiratory infections or diarrhea. Without adequate water, your body can’t sweat to cool itself down. This could lead to heat stroke. When you are exercising outside in the summer, you will need even more water to stay hydrated. For each pound of fluid lost after exercise, you need two to three cups of water to replace that lost fluid.
You should know: The answer above provides general health information that is not intended to replace medical advice or treatment recommendations from a qualified healthcare professional.
See more helpful articles:
The Best Fluids for Staying Hydrated
Make Water Your First Choice for Hydration
The Best Ways to Get (and Stay) Hydrated